# All files / src/chat Tool.ts

87.5% Statements 7/8
50% Branches 6/12
100% Functions 3/3
100% Lines 7/7

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     import { z } from "zod";
    import { toJsonSchema } from "../schema/to-json-schema.js";

    export interface ToolCall {
      id: string;
      type: "function";
      function: {
        name: string;
        arguments: string;
      };
    }

    export interface ToolDefinition {
      type: "function";
      function: {
        name: string;
        description?: string;
        parameters: Record<string, unknown>;
      };
      handler?: (args: unknown) => Promise<string>;
    }

    /**
     * Anything that can be resolved into a ToolDefinition.
     */
    export type ToolResolvable = Tool | { new (): Tool } | ToolDefinition;

    /**
     * Subclass this to create tools with auto-generated schemas and type safety.
     */
    export abstract class Tool<T = Record<string, unknown>> {
      /**
       * The name of the tool (must match [a-zA-Z0-9_-]+).
       */
      public abstract name: string;

      /**
       * A clear description of what the tool does, used by the LLM to decide when to call it.
       */
      public abstract description: string;

      /**
       * Parameters the tool accepts.
       * Can be a Zod object (for auto-schema + type safety) or a raw JSON Schema.
       */
      public abstract schema: z.ZodObject<z.ZodRawShape> | Record<string, unknown>;

      /**
       * The core logic for the tool.
       * 'args' will be parsed and validated based on 'schema'.
       */
      public abstract execute(args: T): Promise<unknown>;

      /**
       * Internal handler to bridge with LLM providers.
       * Converts any result to a string (usually JSON).
       */
      public async handler(args: T): Promise<string> {
        const result = await this.execute(args);
        Iif (result === undefined || result === null) return "";
        return typeof result === "string" ? result : JSON.stringify(result);
      }

      /**
       * Converts the tool definition and logic into a standard ToolDefinition interface.
       * This is called automatically by NodeLLM when registering tools.
       */
      public toLLMTool(): ToolDefinition {
        const rawSchema = toJsonSchema(this.schema);

        // We want the 'properties' and 'required' parts, not the full JSON Schema wrapper if present
        const parameters =
          (rawSchema as { type: string }).type === "object"
            ? rawSchema
            : {
                type: "object",
                properties: (rawSchema as { properties?: Record<string, unknown> }).properties || {},
                required: (rawSchema as { required?: string[] }).required || []
              };

        return {
          type: "function",
          function: {
            name: this.name,
            description: this.description,
            parameters: parameters as Record<string, unknown>
          },
          handler: (args: unknown) => this.handler(args as T)
        };
      }
    }